1. Technical Field
The present invention generally relates to a semiconductor device, and more particularly, to a semiconductor device capable of testing the bonding of a pad.
2. Related Art
A semiconductor chip receives a signal through a pad from an exterior. Generally, the pad of the semiconductor chip is wire-bonded to a terminal of a semiconductor substrate which directly receives an external signal. Recently, in order to reduce the pitch and pad size of a semiconductor chip, a package method using bump bonding, instead of wire bonding, has been proposed. The bump bonding is a method of directly connecting the pad of a memory chip to the terminal of the semiconductor substrate through a bump in a wireless bonding manner. The packaging scheme using bump bonding as described above is called a flip chip.
The use of flip chip bonding enables reduction of the pad size of the semiconductor chip. Therefore, when a scratch or the like occurs on a pad, bump bonding is not normally achieved. When bump bonding is not normally achieved, a semiconductor chip cannot input and output a signal through the pad, so that the semiconductor chip can not sufficiently show the function thereof.
When the bump bonding is not completely formed, it is impossible to input and output a signal through a pad, so that the defects of the bump bonding can be easily detected. However, when bump bonding is incompletely achieved, such as when only a part of the bump bonding is formed, the defects of the bump bonding cannot be easily detected because signals can be inputted and outputted through a pad. When bump bonding is incomplete, an input signal can be delayed, which can cause malfunction of an internal circuit of a semiconductor chip. However, since there is no method of making it possible to accurately detect a partial defect of the bump bonding, it is difficult, when malfunction of a semiconductor chip occurs, to determine whether the malfunction is caused by a defect of bump bonding or by a defect of an internal circuit.